Process for absorbing olefines in strong acids



Patented May 15, 1934 UNITED STATES PROCESS FOR ABSORBING OLEFINEB INSTRONG ACIDS Hendrik Willem Huiiser and Johannes Andreas van Melsen,Amsterdam, Netherlands, aslignorl to Naamlooze Vennootschap DeBataatsche Petroleum Maatschappij, The Hague, Netherlands No Drawing.Application October 15, 1931, Serial No. 569,110. In the NetherlandsNovember 4,

6 Claims.

This invention relates to an improved process for absorbing olefines instrong acids.

It is known to absorb olefines with one or more double bonds in strongacids in the presence of one or more possibly anhydrous metallic-cyanocomplexes.

By means of these catalysts in the first place the formation ofundesirable oily polymerization products, occuring with the knownprocesses for absorbing olefines in strong acids, is almost entirelyavoided.

Moreover the rate of absorption is increased as compared with the knownprocesses for absorbing olefines in strong acids.

It has now been found that the rate of absorption of olefines with oneor more double bonds in strong acids can still be considerablyincreased, without giving rise to the formation of oily polymerizationproducts, by effecting the absorption in the presence of one or morenon-hydrolyzable or practically non-hydrolyzable compounds ofhydrocarbons with one or more double carbon bends in the molecule, suchas propylene, normal butyiene, isobutylene, trimethyl ethylene,diamylene, isoprene, cyclo-hexene, pinene, with metallic-cyanocomplexes, such as ferrocyanide of potassium, ferrocyanic acid orferricyanic acid.

The catalysts according to the invention may prepared e. g. by addingferrocyanide of potassium, ierrocyanic acid or ierricyanic acid toconcentrated or slightly diluted sulphuric acid and thereupon bringingthe hydrocarbon, which is to form the other component of the doublecompound, in liquid or gaseous state into reaction n5 with the liquidobtained.

fire complexes obtained are not readily soluble in oil or pentane, buteasily soluble in ethyl acecats and also in sulphuric acid of anyconcentration, in water and in diluted lye. Some of them 40 can only beseparated by rendering the solution rather strongly alkaline (e. g.54.0% lye) and by heating it, causing the separation of a partlydecomposed product.

It has not been established with certainty whether the double compoundsobtained in this manner and which are to be used as catalysts areaddition products of several single olefine molecules with the complexcyanides used, or addition products of one or more molecules of olefinepolymerides with the complex cyanides.

It is recommendable to prepare the catalysts in the above describedmanner in 90% sulphuric acid and then to dilute the liquid to theconcentration desirable for the absorption proper of 55- oleflnes.

With the process according to the invention not only an improvedasbsorption is obtained, preventing at the same time the formation 01polymerization products, but moreover the limits of the concentration ofacid which can be used for a certain olefine can be considerablywidened. That the latter is of great importance is evident from the factthat in choosing the concentration of the acid the circumstances, underwhich the alkyl sulphuric acids are to be worked up may be taken intoaccount.

The olefines to be absorbed may be applied in the pure or practicallypure state or mixed with other inert or noninert compounds. The olefinesmay be of any origin whatever, they may, for instance, be obtained fromgases or products formed by distilling or cracking petroleum orpetroleum products or by destructive hydrogenation of carbonaceousmaterials.

The olefines to be treated may be previously separated from the abovementioned products, but it is also possible to subject the latterdirectly to the treatment according to the invention.

The invention relates to all kinds of olefines, including those with twoor more double bonds. The reaction may be efiected at ordinary pressureor at a pressure above or below atmospheric pressure, whilst also thetemperature may vary within wide limits.

For absorbing the olefines according to the invention not only sulphuricacid may be used, but also other strong acids, such as phosphoric orsulphonic acids.

Examples 1. 100 cc. of 89.7% sulphuric acid was agitated for one hourwith 5 grams of yellow prussiate of potassium, after which 8 cc. oftrimethyl ethylene was added and agitation continued for hour.

Then propylene was added at a temperature of 28-27 C. at a rate of 3litres gas per hour. Of 10 litres of gas added 9.5 litres were absorbed,whilst no oily polymeride separated out.

In order to ascertain whether the reactionliquicl nevertheless containedpolymerides, the liquid was diluted to 20% sulphuric acid and agitatedwith pentane, after which the pentane was Washed with water, dried anddistilled oil. 0.53 gram of polymericle remained, which, however, didnot proceed from the propylene passed through the sulphuric acid butfrom the trimethyl ethylene used for the catalyst. This appeared fromthe determination of polymerides which was effected as prescribed in aliquid composed entirely according to Example 1 but through which nopropylene had been passed, and in which 0.55 gram of polymeride wasfound. The absorption of propylene may be promoted by adding a smallquantity of isobutylene to the propylene.

2. Into a solution of 100 cc. 90% sulphuric acid and 5 grams K4Fe(CN)531-120 120cm=(=0.28

gram) of gaseous isobutylene were introduced,

after which at 20 C. 10.3 litres of pure propylene gas were introducedat a rate of 3 litres per hour. The absorption amounted to 8.95 litresor 87% of the propylene introduced. The liquid may again be used forpropylene absorption.

3. In a similar manner as described in Example 2 a solution ofisobutylene ferrocyanide double compound in 89.7% sulphuric acid wasprepared, and then diluted to 60% sulphuric acid. Into 260 cc. thereof10 litres of isobutylene were introduced in 4 hours at 20 C. Theabsorption amounted to 9.35 litres.

4. Into 100 cc. 60% sulphuric acid with about 5 grams isobutyleneferrocyanide double compound (prepared according to Example 3) a mixtureof 26.1 volume percent trimethyl ethylene and 73.9% air was introducedat 20 C. at a rate of 3 litres per hour. Of 10.50 litres of gasintroduced 1.80 litres were absorbed. The olefine content of thefinalgas amounted to 10.9%.

5. Propylene was introduced into a solution of 6 grams of yellowprussiate of potassium in 100 00., 100% sulphuric acid at a temperatureof -40 C. After 4 litres of propylene had been absorbed the solution washeated for hour to about 70 C. resulting in the conversion of all theisopropyl sulphuric acid into the desired double compound. The liquid,which had remained clear, was then diluted to 65% acid, after which at atemperature of 22 C. isobutylene was introduced at a rate of 2.9 litresper hour. Of 7.35 litres 5.85 litres, i. e. 79%, were absorbed withoutthe formation of polymerides of any importance.

6. 4.22 litres of normal butylene were absorbed in a solution of 5 gramsyellow prussiate of potassium in 100 cc. 89.7% sulphuric acid. Nopolymeride was formed and the somewhat turbid liquid maintained itsoriginal appearance. After having been left standing for a night,propylene was introduced at a rate of 2.4 litres per hour at atemperature of 21 C. 0f 4.2 litres 4.12 litres or 98% were absorbed. Thetest can be repeated several times with the liquid used before theabsorption efliciency decreases.

7. In 100 cc. 98.8% H2804 to which 5 grams K4Fe(CN)s had been added,2.11 litres of isobutylene were absorbed. After agitating for 4 hour thesolution was diluted to acid. Into 100 cc. of this solution normalbutylene was then introduced at a temperature of 18 C. and at a rate of2.75 litres per hour. After 3% hours 9.24 litres or proved to have beenabsorbed out of 10.32 litres, whilst by pentane extraction 'only 0.2gram of polymerides could be found.

8. To 100 cc. 90% sulphuric acid 5 grams K4Fe(CN)s-and 5 grams purecyclo-hexene were added simultaneously, after which agitation took placeduring one night. Thereupon pure propylene was introduced at 18 C. In 3hours 8.58 litres or 86% of propylene were absorbed out of 9.95 litres.

9. To 100 cc. 90% H2804 5 grams of K4Fe(CN)a were added and thoroughlydistributed by agitating. To the resultant mixture 8 cc. of isoprenewere carefully added drop by drop, after which agitation was repeatedfor 24 hours, The colour of the solution then obtained was brown; asmall quantity of a semi-solid substance floated on the surface and wasremoved. Then propylene was introduced into the clear solution at 17 C.at a rate of 4.4 litres per hour. After 1% hours 5.77 litres out of 5.85litres proved to have been absorbed, i. e. 98%.

10. 5 grams of red prussiate of potassium were agitated for some minuteswith 100 cc. 90% H2804, after which the non-dissolved part was drawnoil. 4 litres of isobutylene were then introduced into the clearsolution, after which again agitation took place for some minutes. Thenpropylene was introduced at 18 C. Of 7.0 litres introduced in 2% hours6.5 litres, or 93%, were absorbed.

It is evident that the invention also includes the absorption ofolefines in the presence of double compounds of a mixture of, forinstance, two hydrocarbons with one or more double carbon bonds in themolecule with .the metalliccyano complexes. Thus it has been found, forinstance, that a double compound of a mixture of trimethyl ethylene andmethyl ethyl ethylene with e. g. ferrocyanide of potassium also promotesthe absorption of propylene in e. g. 90% sulphuric acid.

It is to be observed that the following expressions when used in thespecification and claims have the herein defined meaning. Thus, theexpression under polymerizing conditions means such acid concentrationand such temperature as will polymerize the olefine under treatment. Asthose skilled in the art know, the acid concentration and thetemperature will vary according to the olefine to be polymerized. Ofcourse, such conditions exclude the formation of esters and otherproducts. In the same way, the expression ester-forming conditions meanssuch conditions with regard to temperature and acid concentration thatolefines when led into acid react with the latter to form esters. theterm non-hydrolyzable compounds" means compounds which cannot beconverted into alcohols by means of water.

What we claim is:

1. A process for absorbing olefines having at least one double bond instrong acids and in the presence of at least one metallic cyano complexwhich comprises absorbing olefines under polymerizing conditions in astrong acid containing metallic cyano complexes and resulting inreaction products essentially consisting of substantiallynon-hydrolyzable double compounds consisting of an olefine and themetallic cyano complex to produce an absorption liquid, and subsequentlyabsorbing olefines under esterforming conditions. v

2. The process set forth in claim 1 in which the same olefines areabsorbed inthe second step as are used in the first step.

3. The process set forth in claim 1 in which a concentrated acid isused.

4. The process set forth in claim 1 in which the strong acid has astrength of approximately 90%.

5. The process set forth in claim 1 in which the olefine to be absorbedis in the liquid state.

6. The process set forth in claim 1 in which the olefine to be absorbedis in the gaseous state.

HENDRIK WILLEM HUIJSER. JOHANNES ANDREAS VAN MELSEN.

Furthermore,

